Twist-tie bag closing machine



United States Patent [72] inventor John D. Tetrick White Bear Lake,Minnesota [2i] Appl. No. 706,572

[22] Filed Feb. 19, 1968 v [45] Patented Nov. 10, 1970 [73] AssigneeDoughboy industries, Inc.

New Richmond, Wisconsin a corporation of Wisconsin [54] TWIST-TIE BAGCLOSING MACHINE 3,369,573 -2/l968 Bakeretal Primary ExaminerLowell A.Larson Attorney-Williamson, Palmatier and Bains ABSTRACT: A machine forclosing the open, gathered ends of flexible bags incorporates arotatably mounted cam plate and roller assembly which serves to carryout the several functions of feeding a length of tying strip intoposition, actuating a knife which cuts off the desired length of tyingstrip, drives a forming arm which forms the ribbon in a loop around theneck of the bag to be closed, and actuates the drive mechanism forrotating the hooked twister which twists the ends of the tying striptogether. A clutch mechanism connected to the drLvc shaft for the camplate and roller assembly is arranged to be engaged and disengaged by amovable member which is actuated by the neck of a bag when it is movedinto position to be closed by the tying machine.

' Panama Nov. 10,1970 5 3,538,960

, Sheefiof? mvsw'roa Jo /v D. TETE/GK A fro/24151 5 Patnted Nov. 10,1970

Sheet I 'INVENTOR.

Jew/M2. TETE/CK 1 TWIST-TIE BAG CLOSING MACHINE Packaging machines ofthe type which close the open, gathered ends of flexible bags, such asthe plastic bags in which produce and bakery goods are packaged, bytwisting a flexible tie strip around the neck of the bag are known andin widespread use. Most of these machines are designed and constructedto accommodate a production line type of operation wherein bags to bepackaged are fed by the machine on a conveyor, and the gathering andtying of the bag neck are carried out automatically. Production linemachines of this type are necessarily quite sophisticated and expensive.

l have developed a small, twist-tying machine, which is particularlydesigned for but not limited to manual operation, and which isparticularly characterized by its simplicity of construction andoperation.

These desirable objectives are obtained by virtue of an operatingmechanism which incorporates as its basic operating component a camassembly which initiates all of the necessary mechanical steps in thetying operation as it moves through the predetermined path. Not onlydoes the aforesaid cam assembly actuate the tying strip feed and cutoffdevices, but it also operates a linkage mechanism for moving a formingarm which bends the tying strip back on itself around the neck of a bag.

As a further advantageous feature of my improved tying machine, the camassembly is arranged to actuate a rotating mechanism for a twister hookwhich twists the ends of the tying strip together, the cam assemblybeing moved to initiate this twisting operation after the tie stripforming step has been completed.

A particularly unique and important feature of my invention resides inthe utilization of a movable member responsive to the movement of a baginto a tying position at the head of the machine to engage and disengagea clutch which transmits rotary power to a drive shaft for the aforesaidcam assembly.

These and other objects and advantages of my invention will becomereadily apparent as the following description is read in conjunctionwith the accompanying drawings. wherein like reference numerals are usedto refer to like elements throughout the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of the tyingmachine of this invention with the various parts shown in the positionthey will assume prior to the initiation of a tying operation;

FIG. 2 is a perspective view of the double-hook tying device; I

FIG. 3 is a perspective view showing the cooperative relationship of thetying strip cutoff knife and cutting block;

FIG. 4 is a top view similar to FIG. 1 showing the operative parts at anintermediate stage of the tying operation;

FIG. 5 is a top view of the tying machine showing the parts in theposition they will assume as the tying operation is being completed;

FIG. 6 is an enlarged, fragmentary view showing the twister inengagement with the ends of the tying strip;

FIG. 7 is a bottom view of the tying machine showing the clutch anddrive mechanism;

FIG. 8 is am exploded perspective view of the clutch mechanism; and

FIG. 9 is a perspective view of a bag having a gathered neck tied by themachine of this invention.

The bag tying apparatus of this invention is shown in FIG. 1 as mountedon a plate ll having a head 2 which is slotted at 4 to accommodate thegathered neck of a bag. Head 2 is normally covered by a housing andinfeed guide member 6. A spool 8 carrying a roll of tying ribbon 10 isrotatably mounted within recess 12 of plate 1 on shaft 14. Ribbon 10 maybe any strip of material which is flexible, and capable of holding atwisted shape. Paper or plastic coated wire has been found to beparticularly suitable for this purpose. Ribbon 10 is taken off the topof spool 8 and directed over the top of brake arm l6 through guidesleeve 18 to a feed mechanism. Brake arm 16 is pivotally mounted at itslower end to support bar 20, and normally rests on the top of spool 8 toprevent the uncoiling of tying ribbon 10. When ribbon 10 is pulled bythe advancing mechanism described below, it will lift arm 16 allowingspool 8 to rotate and release the desired amount of ribbon.

In order to prepare the tying machine for operation, tape All is fed byhand between rotatably mounted, rubber idler wheel 22 and cam surface 24of cam plate 26. The end of tape it) is then directed through guidesleeve 28, and aperture 36 in entoff block 32. Slotted guide member 34adjacent cutting block 32 serves to guide ribbon 10 forwardly to theouter extremity of pivotally mounted forming finger 3, which has aribbonforming recess 38 therein. Forming finger 36 is pivoted aboutpoint 39 by interconnected links 14) and 41 assembled at the forward endof arm 42. Arm 42 pivots about point 4-3, and carries ribbon cutoffknife 44- on the inside face of its forward end. As is best shown inFIG. 3, knife 4% is positioned adjacent forward face 31 of cutting block32, and cooperates therewith to sever ribbon 10 as arm 42 is pivoted inthe direction indicated by the arrow.

Pivotal movement is imparted to arm 42 by roller cam 46 which isrotatably mounted on cam plate 26 to form a unitary cam assemblytherewith. Cam plate 26 extends between arm 42 and plate 1 in order topermit cam surface 2 thereof to drivingly engage ribbon llll againstidler 22 as well as to allow carn roller 46 to engage indented followersurface .-8 on arm 42. Cam plate 26 is rotated by a drive mechanismhereinafter described in order that cam surface 24 and roller 46 mayinitiate the ribbon feeding, cutoff, forming and tying operations asdescribed below.

For the purpose of twisting the ends of a length of ribbon it togetherso as to tightly close the neck of a bag, I provide hook 50 mounted onthe end of rotatably supported shaft 52. With reference to FIG. 2, hook50 is provided with oppositely turned hook end portions Sll and 53 whichengage the op posite ends of a length of tying ribbon as shaft 52 isrotated. Shaft 52 is rotated by means of a pull cord 54 which is coiledaround shaft 52 and fastened thereto at one end 55. Referring again toFIG. 1, a coil spring 56 is also secured to shaft 52 and serves toreturn it to its rest position after pull cord 54 has been released.

One end of pull cord 54 is attached to linkage arm 58, which has gear 60connected to one end thereof and is rotatable therewith about pivotpoint 62. The teeth on gear 66 mesh with the teeth on drive gear 64which is rotated by linkage arm 66 to which it is connected. Therotational movement of arm 66 about pivot point 6% so as to accomplishthe actuation of pull cord 54 is achieved by rotating roller cam 46against the upper end of arm 66. Attached to the upper end of linkagearm 66 at floating pivot point'70 is link 72 which is connected to armAll by means of slot '74 therein.

For the purpose of rotating the assembly of cam plate 26 and roller 46so as to carry out the various steps in a bag tying operation, I providea drive mechanism which will now be described with reference to FIGS. 7and 8. Connected to the underside of cam plate 26 and extendingdownwardly therefrom through an aperture 76 in plate 1 is a drive shaft76. Rotatably supported on the lower end of drive shaft 76 below plate1, as viewed from its bottom side in FIG. 7, is a sprocket assembly 80'.Sprocket assembly 80 is held in place on shaft '76 by a collar 82, andis comprised of a sprocket wheel SM and a star wheel 86. A drive chain$8 extends around sprocket wheel 84 and is connected at its opposite endto a similar drive sprocket connected to the output shaft of a motor(not shown). Rotary power is intermittently transmitted to earn driveshaft 76 from sprocket assembly 80 by a clutch mechanism consisting ofclutch arm and clutch dog 92. Clutch arm 90 is drivingly connected tocam shaft 76 by a pin 94 extending through collar 96 and an aligned holedrilled through the lower end of shaft 76. A bushing 98, and one-wayclutch 100 are also mounted on the lower end of drive shaft '76 betweenthe bottom of plate I and collar 96 of clutch arm 9% One-way clutch 100insures that cam plate 26 will rotate in only the desired direction.Clutch dog 92 is pivotally secured to arm 90 by means of pin 102, whichextends through bushing 104 in arm 90 and has grip ring 106 attached toits upper end. Release pin lllfl for clutch dog 92 extends upwardlytherefrom. Clutch dog 92 is biased towards a position in drivingengagement with star wheel 86 by spring 110. A clutch actuating assemblyconsisting of pivotal arm 112 having fingers 113 and 114 at its oppositeends serves to hold clutch dog 92 in a normal position out of engagementwith star wheel 36. Arm 112 is pivotally connected to plate 1 by meansof cap screw 116, sleeve 118, and bushing 120. Spring 122 urges arm 112towards the normal position indicated in phantom lines in FlG. 7 whereinfinger 114 engages pin 108 and holds dog 92 out of contact with starwheel 86. Slide bar 12 extending in alignment with slot 4 is connectedat its inner end to arm 112. Outer end 125 of slide bar 124 overlaps theinner end of slot 4 in position to be contacted by the neck ofa baginserted within slot 4.

in order to ready the tying machine for operation, the motor to whichdrive sprocket 88 is connected is started, thereby causing sprocketassembly 80 to rotate. in order to engage the clutch mechanism and startcam shaft 76 rotating, the gathered neck portion R28 of a bag 126 isinserted into slot 4 and forced against end 125 of slide bar 124,thereby forcing bar 124- to the left in the direction indicated by thesolid arrow in FlG. 7. The inward movement of slide bar 124 will pivotclutch actuating arm 112 from the phantom line position to the solid ineposition shown in FlG. 7. Finger 114 will thus be moved out ofengagement with pin 108 on dog 92, thereby permitting spring 120 to pulldog 92 into one of the pockets in star wheel 86. As star wheel 86continues to rotate it will engage dog 92. and force clutch arm 90 torotate in the direction indicated by the arcixtte arrow. Cam drive shaft76, being connected to collar 96 of clutch arm 90, will rotatetherewith, thus starting cam plate 26 and roller 46 to rotate through apredetermined operational path. Assuming that cam plate 26 is in theposition shown in FlG. 1 with a length of tying strip already havingbeen advanced into position, the rotation of cam plate 26 by shaft 76will bring roller 46 into engagement with follower surface 48 of arm 42.As roller 46 bears against arm 5-2 in the manner shown in FIG. 4, arm 42will pivot in a counterclockwise direction so as to move cutting knife44- across cutoff block 32 to sever a length 11 of the tying ribbon.This same movement of pivotal arm 42 will cause links 40 and 41connected thereto to simultaneously swing forming fingers 36 about pivotpoint 39 to the position shown in FIG. 4. As finger 36 rotates aroundpivot point 39 recess 33 therein will bend ribbon strand it around bagneck 128 to the position shown in FIG. 4. As cam plate 26 continues torotate, roller cam 46 will be brought to bear against the upper end oflinkage arm 66 thereby moving arm 66 in a clockwise direction asindicated by the arrows in FlG. 5. As arm 66 pivots about point 68, gearattached thereto will rotate in the same direction, thereby driving gear60 in a counterclockwise direction. Linkage arm 58 connected to gear 60will thus rotate in the same direction about pivot point 62, therebyexerting a pulling force on cord 54. As cord 54 is pulled by linkage arm58 shaft 52 will rotate, and hook 50 at the outer end thereof willtwist-tie ribbon strand ll about neck 12% of bag 126.

The ribbon twisting action of rotary hook 56 is best illustrated in FlG.6. Oppositely turned, hooked end portions Si and 53 of hook 50 willengage opposite ends 13 and 15 of riblion strand ll and twist themtogether from the end ofshaft 52 towards bag neck 126. As a result ofthe uniform twisting action of double hooks 51 and 53, ends 13 and 15 ofribbon strand it will be tied together in a tight, even twist.

As cam roller 46 moves from the position shown in FIG. 4 to that shownin FIG. 5, linkage arm 66 will first push floating link 72 through alost motion path in which slot 74 therein :nidcs upwardly over fastener75 secured to arm 42. During this time arm 42 will thus be maintained inthe position shown in FlGS. and 5 wherein forming finger 36 holdswrapper strand 11 around bag neck 126 while linkage arm 66 rotates asufficient distance to carry out the aforesaid twisting opera tion byhook 5t Slot 74 is of such a length that it will move back and forthover fastener 75 on arm 4-2 as linkage arm 6f.- movcs to effect theribbon twisting operation. As roller "16 continues to rotate against arm66, the further clockwise movement thereof will bring the outer end ofslot 74 to bear against fastener 75, and arm 42. will he pulled back tothe starting position shown in FIG. 1. As cam drive shaft 76 continuesto rotate roller 46 through the arcuate path indicated at 45 in FIG. 5,roller 46 will eventually be moved out of engagement with linkage arm66. When this happens, coil spring wrapped around hook shaft 52 willexert a counterrotational force on shaft 52, whereby cord 54 will pulllinkage arm 58 back to its original position. The return pivotalmovement of arm 58 will cause linkage arm to also rotate back to itsoriginal position by the mechanism of meshing gears 60 and 64. At thistime, cam roller 46 will have gone through approximately two thirds ofarevolution. lf bag neck 128 is left in slot 4 in engagement with slidebar 124, clutch actuating bar 2.1.2 will be maintained in the solid lineposition shown in FlG. 7, and finger 1. 13 thereof will interact withrotating clutch dog If. to prevent the further rotation of cam driveshaft 76. After clutch dog 92 has rotated through two thirds of arevolution from the solid line position shown in FIG. 7. release pin 1C3attached thereto will strike finger 113 thereby forcing dog 92 out ofengagement with star wheel When bag neck i233 is removed from slot 4,spring 122 will act to pivot clutch actuating arm 112 to the phantomline position shown in FlG. 7. /'.s a result, finger US will release pinROS and clutch dog 92 and Clutch arm will continue to rotate until finge1E4 disengages dog 92 from star wheel 86. Drive shaft 76 will now havecompleted one complete revolution. During the last one third of thisrevolution, the rotation of cam plate 26 will move earn surface 24thereof through an arc in cooperative engagement with idler 22, wherebyanother length of tying ribbon will be advanced therebetween to thetying position shown in FIG. 1. The machine is now ready to beginanother cycle of operation. It is to be noted that spring biased bar l9wedges ribbon 10* against guide block 18 so as to prevent ribbon .41from moving in a reverse direction after the required length for a tyingoperation has been cut off.

lf bag neck 128 is removed from slot 4 after drive shaft 76 hascompleted two thirds of a revolution, spring 1.22 will pivot clutchactuating bar 112 back to the phantom line position shown in FlG. 7.Finger 113 will thus be removed from the path of dog release pin 103,and cam shaft 76 will continue to rotate so as to advance an additionallength of rib on into tying position. After drive shaft 76 has completedone revolution, finger 114 will strike release pin 108 and disengageclutch dog 92 from star wheel 86.

FIG. 9 shows bag 126 with its gathered neck 123 closed by twisted ends13 and 15 of ribbon strand 1!.

Although my improved bag tying machine is primarily designed for manualoperation wherein a bag neck is gathered by hand and then moved in andout of slot manually. it would be possible to adapt my machine to ahigher volume production operation wherein the bags move along on aconveyor and are automatically moved in and out of slot 4. The tyingmachine will normally be mounted with plate l disposed horizontally.Base 3 shown in FlG. may be utilized to support plate I in the desiredhorizontal position.

Those skilled in the art will readily appreciate tha the unique drivearrangement described above wherein a single cam assembly comprised ofcum plate 26 and roller -35 cooperates with various linkages to as tocarry out all of the necessary steps in the tying operation greatlyminimizes the number and complexity of moving parts. The constructionand operation of the machine is thus greatly simplified, therebysignificantly reducing construction and maintenance costs. The novelbag-actuated clutch mechanism permits the drive motor to be runcontinuously with the tying operation being started and stopped as a bagneck is moved in and out ofslot 4.

tightly l contemplate that various changes may be made in the form,details, arrangement and proportions of the various parts withoutdeparting from the spirit and scope of my invention as defined by thefollowing claims.

I claim:

1. ln a bag tying machine having mechanisms for feeding a strip ofribbon into position to tie a bag, cutting off the ribbon strip, formingthe strip around the neck of the bag and twisting the ends of the ribbonstrip together, improved actuating means for said mechanisms comprising:

a rotatably mounted cam member having cam elements thereon operative toengage and actuate said mechanisms as said elements move through apredetermined path, said cam elements comprising an extended surface onsaid cam member and a second cam element secured thereto for rotationtherewith, said ribbon cutting, forming and twisting mechanisms havingactuating elements disposed in the path of said second cam element foroperation thereby in' a predetermined sequence as said second camelement rotates through said predetermined path, and further including;and

an idler wheel with which said extended surface on said cam membercooperates to feed a strip of ribbon therebetween as said cam memberrotates.

2. A bag tying machine as defined in claim 1 wherein said mechanism forcutting off said ribbon strip comprises a knife mounted on an actuatingelement in the form of a pivotal arm which reciprocates said knife backand forth across the path of said ribbon in response to the movement ofsaid second cam element thereagainst.

3. A bag tying machine comprising:

means for advancing a strip of tying ribbon from a ribbon roll intoposition to be secured around the neck of a bag;

a pivotally movable knife for cutting off said strip of ribbon;

a pivotally mounted forming finger for looping said ribbon strip aroundsaid bag neck;

common actuating means for said knife and forming finger operativelyassociated therewith for moving said knife and finger so as to cutoffand loop said ribbon strip; and

actuating means comprises a pivotal arm to which said knife I andforming finger are connected, whereby the movement of said arm as it isengaged by said cam element simultaneously actuates said knife and saidforming finger.

S. A bag tying machine as defined in claim 4 and further including:

a twisting hook for twisting the ends of said strip of tying ribbontogether, said hook being mounted on a rotatably supported shaft; and

drive means for rotating said shaft, said drive means including anactuating element therefor disposed in said path of said movable camelement, whereby said drive means is operated by the movement of saidcam element against said actuating element.

6. A bag tying machine as defined in claim 5 wherein:

said drive means for said twisting hook comprises a pull cord wrappedaround said shaft and having one end secured to pull means;

said actuating element for said drive means comprises a pivotal linkagearm operatively associated with said pull means, the pivotal movement ofwhich by said cam element operates said pull means to rotate said hookshaft; and further including a return spring connected to said hookshaft and operative to return said shaft, pull means and linkage arm totheir rest positions after said cam element rotates out of engagementwith said linkage arm.

7. A bag tying machine as defined in claim 5, and further including aconnecting link extending between said actuatin element for said drivemeans and said pivotal arm, said hn being operative to return said arm,and said knife and forming finger therewith, to their rest positions bythe pivotal movement of said actuating element at the termination of theribbon twisting operation.

